Oracle UCM : Oracle Universal Content Management.

Starting in Oracle 11g release 2,
Oracle has renamed the flash recovery area to the fast recovery area (also simply called the recovery area), which automates management of backup-related files.

The Fast Recovery Area is a location in which Oracle Database can store and manage files related to backup and recovery.

in 11g R1 , It is flash recovery area, But this is changed to fast recovery area in 11g r2.
Default fast recovery area: $ORACLE_BASE/recovery_area
db_recovery_file_dest - flash_recovery_area - This is the location of the flash recovery area.
This can be a directory, file system, or Automatic Storage Management (Oracle ASM) disk group. It cannot be a raw file system.

db_recovery_file_dest_size - Specifies the maximum total bytes to be used by the Fast Recovery Area.

In an Oracle RAC environment, the settings for these two parameters must be the same on all instances